Add basic type substitution

1 files changed, 122 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java b/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java
new file mode 100644
index 00000000..662eebcc
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java
@@ -0,0 +1,122 @@
+package org.shedlang.compiler.types;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class TypeSubstitutionTests {
+    private static final NamespaceName NAMESPACE_NAME = NamespaceName.of("Example", "Project");
+    private static final StructType STRUCT_TYPE = Types.struct(NAMESPACE_NAME, "Struct");
+    private static final StructType STRUCT_TYPE_2 = Types.struct(NAMESPACE_NAME, "Struct2");
+
+    @Test
+    public void substitutingBoolDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(Types.BOOL, typeSubstitutionMap);
+
+        assertThat(result, equalTo(Types.BOOL));
+    }
+
+    @Test
+    public void substitutingBottomDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(Types.BOTTOM, typeSubstitutionMap);
+
+        assertThat(result, equalTo(Types.BOTTOM));
+    }
+
+    @Test
+    public void substitutingIntDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.BOOL)
+        );
+
+        var result = TypeSubstitution.substitute(Types.INT, typeSubstitutionMap);
+
+        assertThat(result, equalTo(Types.INT));
+    }
+
+    @Test
+    public void substitutingNamespaceDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(
+            Types.namespace(NamespaceName.of("A")),
+            typeSubstitutionMap
+        );
+
+        assertThat(result, equalTo(Types.namespace(NamespaceName.of("A"))));
+    }
+
+    @Test
+    public void substitutingStringDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(Types.STRING, typeSubstitutionMap);
+
+        assertThat(result, equalTo(Types.STRING));
+    }
+
+    @Test
+    public void substitutingTopDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(Types.TOP, typeSubstitutionMap);
+
+        assertThat(result, equalTo(Types.TOP));
+    }
+
+    @Test
+    public void substitutingTypeParamDoesNothingIfTypeParamIsNotInSubstitutionMap() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(
+            TypeParam.forStructType(STRUCT_TYPE_2, "T"),
+            typeSubstitutionMap
+        );
+
+        assertThat(result, equalTo(TypeParam.forStructType(STRUCT_TYPE_2, "T")));
+    }
+
+    @Test
+    public void substitutingTypeParamChangesTypeParamToCorrespondingType() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(
+            TypeParam.forStructType(STRUCT_TYPE, "T"),
+            typeSubstitutionMap
+        );
+
+        assertThat(result, equalTo(Types.INT));
+    }
+
+    @Test
+    public void substitutingUnitDoesNothing() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(Types.UNIT, typeSubstitutionMap);
+
+        assertThat(result, equalTo(Types.UNIT));
+    }
+}